MCP98243 Microchip Technology Inc., MCP98243 Datasheet - Page 37

• Manufacturer Part Number: MCP98243
• Description: Memory Module Temperature Sensor W/ Eeprom For Spd
• Manufacturer: Microchip Technology Inc.

5.3.3
The MCP98243 has a Software Write-Protect (SWP)
feature that allows the lower half array (addresses
00h - 7Fh) to be write-protected or permanently write-
protected (PWP). The write protected area can be
cleared by sending Clear Write Protect (CWP)
command. However, once the PWP is executed the
protected memory can not be cleared. The device will
not respond to the CWP command.
TABLE 5-4:
TABLE 5-5:
© 2009 Microchip Technology Inc.
Note 1:
Permanently
Note 1: X is defined as ‘don’t care’.
Protected
Protected
Protected
Status
PWP (Note)
SWP
EEPROM
with
Not
SWP
CWP
The Address Pins are ‘X’ or don’t cares. However, the slave address bits need to match the address pins.
For V
WRITE PROTECTION
HV
WRITE PROTECT DEVICE ADDRESSING (NOTE 1)
DEVICE RESPONSE WHEN WRITING DATA OR ACCESSING SWP/CWP/PWP
(NOTE 1)
Page/byte write lower 128 bytes
Page/byte write lower 128 bytes
voltage levels, refer to
SWP/CWP/PWP
SWP/CWP/PWP
Page/byte write
Operation
Command
WRITE
WRITE
WRITE
READ
READ
READ
SWP
CWP
PWP
Figure
GND GND
GND V
A2
X
Address Pins
2-13.
A1
NoACK
NoACK
X
DD
ACK
ACK
ACK
ACK
ACK
ACK
ACK
V
V
A0
X
HV
HV
To access write protection, the device address code of
the Address Byte is set to ‘0110’ instead of ‘1010’. The
‘1010’ Address code is used to access the memory
area and the ‘0110’ address code is used to access the
write protection. Once the device is write protected it
will not acknowledge certain commands.
shows the corresponding Address Bytes for the write
protect feature.
Address
Address
Address
Address
X
X
X
X
X
Address Code
0110
0110
0110
NoACK
NoACK
ACK
ACK
ACK
ACK
ACK
ACK
ACK
Data Byte
Address Byte
Data
Data
Data
A2
X
X
X
X
X
Slave Address
X
0
0
MCP98243
A1
X
0
1
NoACK
NoACK
NoACK
NoACK
ACK
ACK
ACK
ACK
ACK
DS22153A-page 37
A0
X
1
1
Write Cycle
Table 5-4
Yes
Yes
Yes
Yes
No
No
No
No
R/W
0
1
0
1
0
1